A freezing method for suppressing myofibrillar protein denaturation using a magneto-electric coupling field

Abstract

The present application relates to the technical field of frozen fish products, and particularly relates to a frozen method for inhibiting myofibrillar protein denaturation by using a magnetoelectric coupling field, which comprises the following steps: taking back white meat after fish processing, washing and chopping, and then soaking in a compound deodorizing solution to obtain deodorized fish meat; draining after vacuum impregnation in a compound antifreezing agent solution, vacuum packaging, processing in an ultrahigh pressure equipment processing cavity, adding glutamine transaminase, uniformly mixing, microwave crosslinking treatment, impregnation in a beta-cyclodextrin compound embedding dispersion solution, and frozen storage in a magnetoelectric coupling freezing equipment to obtain a frozen fish product. The present application uses the above steps, uses a static magnetic field and a low-voltage electrostatic field to couple freezing, inhibits the generation of large-size ice crystals, makes the ice crystals formed in the freezing process small and uniformly distributed, and maximally retains the solubility, gel activity and functional properties of myofibrillar protein.

Description

Technical Field

[0001] This invention relates to the field of frozen fish products, and in particular to a freezing method that utilizes a magnetoelectric coupling field to inhibit myofibrillar protein denaturation. Background Technology

[0002] Fish meat is tender, high in protein, low in fat, and rich in unsaturated fatty acids, amino acids, and various trace elements, making it a high-quality, high-protein aquatic food that is very popular with consumers. However, fresh fish meat has a high water content, fragile tissue, and is prone to microbial growth. Furthermore, myofibril protein, a core functional protein in fish meat that maintains its texture, elasticity, and nutritional value, has extremely poor stability. During traditional freezing, storage, and processing, it is very easy to denature, aggregate, and degrade, leading to a deterioration in the quality of the fish meat. This severely restricts the deep processing and long-term preservation of both freshwater and saltwater fish.

[0003] Currently, the aquatic product industry commonly uses traditional low-temperature freezing, quick-freezing, and refrigeration methods for preservation and processing. These technologies have several inherent drawbacks. First, during traditional freezing, the internal moisture of fish meat easily forms large ice crystals, which can pierce the muscle cell structure, disrupt the spatial conformation of myofibril proteins, and cause protein denaturation, reduced solubility, and decreased gel properties. Ultimately, this results in high juice loss, loose texture, poor elasticity, and a tough, dry mouthfeel after thawing, significantly reducing the edible quality and commercial value of the fish. Second, fresh fish meat naturally contains fishy-smelling substances. Traditional rinsing with water has limited effectiveness in removing this odor, only removing volatile surface fishy components and failing to degrade endogenous fishy-smelling substances such as trimethylamine and hydrogen sulfide within the fish meat. During frozen storage, the fishy odor continues to leach out and intensify, severely affecting the product's flavor.

[0004] Magnetoelectric coupling fields, as a novel physical preservation technology, can regulate water molecule arrangement, inhibit ice crystal growth, and stabilize biological protein structures through the synergistic effect of magnetic and electric fields. Compared with traditional freezing technologies, they have significant technical advantages. However, a complete process suitable for fish processing and capable of efficiently inhibiting myofibrillar protein denaturation has not yet been developed. Based on this, this invention proposes a freezing method that utilizes magnetoelectric coupling fields to inhibit myofibrillar protein denaturation. This method combines deodorization pretreatment, ultra-high pressure modification, enzymatic gel crosslinking, composite embedding, and magnetoelectric coupling freezing into an integrated process, addressing the technical pain points of existing technologies such as easy denaturation of fish proteins, significant ice crystal damage, poor flavor, and deterioration of texture. Summary of the Invention

[0005] The purpose of this invention is to provide a freezing method that uses a magnetoelectric coupling field to inhibit myofibrillar protein denaturation, thereby solving the above-mentioned problems.

[0006] To achieve the above objectives, the present invention provides a freezing method for inhibiting myofibrillar protein denaturation using a magnetoelectric coupling field, comprising the following steps: S1. After processing the fish, take the white meat from the back, wash it, chop it, soak it in the compound deodorizing solution, soak it at 30-40℃ for 30-60 minutes, rinse it and drain it to get the deodorized fish meat. S2. Place the deodorized fish meat from S1 into a compound antifreeze solution, vacuum impregnate and then drain to obtain pre-treated deodorized fish meat. S3. After vacuum packaging the pretreated deodorized fish meat obtained in S2, it is processed in the processing chamber of an ultra-high pressure equipment to obtain ultra-high pressure treated fish meat. S4. Add transglutaminase to the fish meat treated with ultra-high pressure in S3. The mass of transglutaminase is 0.2-0.6% of the fish meat treated with ultra-high pressure. After mixing evenly at 4°C, microwave cross-linking treatment is performed to obtain the gelled fish meat. S5. The fish meat that has undergone gelation treatment in S4 is immersed in a β-cyclodextrin composite encapsulation dispersion, encapsulated at 4°C for 20-40 min, and then vacuum-packed and frozen in a magnetoelectric coupling freezing device to obtain frozen fish products.

[0007] Preferably, in S1, the composite deodorizing solution is a sodium alginate-chitosan co-immobilized biological enzyme-yeast composite deodorizing solution, and the soaking material-liquid ratio is 1:3.

[0008] Preferably, the co-immobilized bio-enzymes in the sodium alginate-chitosan co-immobilized bio-enzyme-yeast composite deodorizing solution are neutral proteases and flavor proteases, the amount of co-immobilized bio-enzymes added is 0.8-1.2% of the mass of the composite deodorizing solution, and the mass ratio of sodium alginate to chitosan is 1:1-2.

[0009] Preferably, in S2, the components of the compound antifreeze solution include 2-4 parts by mass of trehalose, 0.5-2 parts by mass of sodium citrate, 0.2-1 parts by mass of hydroxyproline, and 100 parts by mass of deionized water, and the pH is adjusted to 6-6.8.

[0010] Preferably, in S2, vacuum impregnation is performed at 0-4°C and a vacuum of -0.08 to -0.1 MPa for 20-40 minutes.

[0011] Preferably, in S3, the treatment in the ultra-high pressure equipment is to maintain the pressure at 200-300MPa for 5-15 minutes.

[0012] Preferably, in S4, the microwave crosslinking treatment is performed at 40-50°C with a microwave power density of 0.5-1.5 W / g for 30-90 min.

[0013] Preferably, the ratio of the gelled fish meat and the β-cyclodextrin composite encapsulation dispersion in S4 is 1:2.

[0014] Preferably, in S5, the static magnetic field strength in the magnetoelectric coupling refrigeration equipment is 4-6 mT, the input voltage of the low-voltage electrostatic field is 220 V, the maximum current is 0.2 mA, and the electric field strength between the plates is 100-200 V / m.

[0015] Preferably, in S5, the β-cyclodextrin complex encapsulation dispersion comprises, by mass, 8-12 parts of β-cyclodextrin, 2-3 parts of maltodextrin, 0.5-1 parts of fish skin collagen peptide, and 100 parts of deionized water.

[0016] Therefore, the present invention employs the above-mentioned freezing method for inhibiting myofibrillar protein denaturation using a magnetoelectric coupling field, and its beneficial effects are as follows: 1. The freezing method provided by this invention adopts a composite deodorization system of sodium alginate-chitosan co-immobilized neutral protease, flavor protease and yeast. Compared with traditional physical deodorization and single enzyme deodorization methods, it has significant advantages. The co-immobilized biological enzyme has stronger stability and higher enzymatic hydrolysis efficiency. It can accurately degrade protein decomposition products and endogenous fishy odor precursors such as trimethylamine inside the fish meat. The yeast can adsorb volatile fishy odor components. Combined with the precise material-liquid ratio and temperature soaking process, it can achieve simultaneous internal and external deodorization and completely remove the original fishy odor of the fish meat. 2. The compound antifreeze agent provided by this invention uses a compound ratio of trehalose, sodium citrate, and hydroxyproline, combined with a low-temperature vacuum impregnation process, to achieve rapid and uniform penetration of antifreeze components into the interior of fish muscle tissue. Trehalose can form a protective film on the surface of protein molecules, stabilizing the spatial conformation of myofibril proteins; sodium citrate can regulate the pH value of the system and inhibit protein aggregation and precipitation; hydroxyproline can strengthen the toughness of fish tissue structure. The three components work synergistically to effectively reduce the damage to protein structure caused by low temperature environment and inhibit the denaturation and degradation of myofibril proteins. 3. This invention uses an ultra-high pressure pretreatment process, which can gently modify fish myofibrillar protein, moderately unfold the protein molecular chains, enhance protein activity and cross-linking ability, and will not cause protein denaturation damage. Combined with transglutaminase and microwave cross-linking treatment with precise power density and temperature, it can induce myofibrillar protein molecules to undergo covalent cross-linking, forming a dense and uniform protein gel network structure. 4. This invention uses a static magnetic field coupled with a low-voltage electrostatic field for freezing. The 4-6mT static magnetic field can regulate the hydrogen bond arrangement of water molecules inside the fish meat, inhibiting the formation of large-sized ice crystals, making the ice crystals formed during freezing small and evenly distributed, avoiding ice crystals piercing muscle cells and damaging the spatial structure of proteins. The 100-200V / m low-voltage electrostatic field can maintain the polarity balance of protein molecules, inhibit the unfolding, aggregation and denaturation of myofibril proteins, and maximize the preservation of the solubility, gel activity and functional properties of myofibril proteins.

[0017] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0018] Figure 1 These are the texture property diagrams of Examples 1-3 and Comparative Examples 1-3 of the present invention; Figure 2 This is a SEM image of the frozen fish product in Embodiment 3 of the present invention. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments. Unless otherwise defined, the technical or scientific terms used in this invention should be understood in their ordinary sense by those skilled in the art. The features mentioned above or in the specific examples mentioned in this invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the invention and are not intended to limit the scope of the invention.

[0020] This invention provides a freezing method for inhibiting myofibrillar protein denaturation using a magnetoelectric coupling field, comprising the following steps: S1. After processing the fish, remove the white meat from the back, wash and chop it, then soak it in a compound deodorizing solution at 30-40℃ for 30-60 minutes. Rinse and drain to obtain deodorized fish meat. Selecting and chopping the white meat from the back aims to obtain a homogeneous raw material with high myofibril protein content and low fat content. The soaking temperature is within the optimal range for enzymatic hydrolysis and yeast action, ensuring activity without causing denaturation of the fish meat protein.

[0021] S2. Place the deodorized fish meat from S1 into the compound antifreeze solution, vacuum impregnate and drain to obtain pre-treated deodorized fish meat; allow the compound antifreeze protectant to penetrate deep into the fish meat to provide protection for subsequent freezing.

[0022] S3. After vacuum packaging the pretreated deodorized fish meat obtained in S2, it is processed in the processing chamber of an ultra-high pressure equipment to obtain ultra-high pressure treated fish meat. S4. Add transglutaminase (TG) to the fish meat treated under ultra-high pressure in S3. The mass of TG is 0.2-0.6% of the mass of the fish meat treated under ultra-high pressure. After mixing evenly at 4°C, perform microwave cross-linking treatment to obtain gelled fish meat. Transglutaminase (TG enzyme) can catalyze the formation of covalent bonds between myosin molecules, thereby significantly improving the gel strength, elasticity, and water-holding capacity of the protein. Microwave cross-linking enhances the activity of transglutaminase, and the microwave field promotes the aggregation of protein molecules.

[0023] S5. The gelled fish meat from S4 is immersed in a β-cyclodextrin composite encapsulation dispersion, encapsulated at 4°C for 20-40 min, then vacuum-packed and frozen in a magnetoelectric coupling freezing device to obtain frozen fish products. Magnetoelectric coupling can significantly accelerate the freezing rate, thereby reducing the size of ice crystals and making their distribution more uniform. This reduces the mechanical damage of large ice crystals to muscle fibers and cell structures, and can also effectively inhibit protein oxidation and denaturation.

[0024] In some embodiments of the present invention, in S1, the composite deodorizing solution is a sodium alginate-chitosan co-immobilized biological enzyme-yeast composite deodorizing solution, and the soaking material-liquid ratio is 1:3.

[0025] In some embodiments of the present invention, the co-immobilized bioenzymes in the sodium alginate-chitosan co-immobilized bioenzyme-yeast composite deodorizing solution are neutral proteases and flavor proteases. The amount of co-immobilized bioenzymes added is 0.8-1.2% of the mass of the composite deodorizing solution, and the mass ratio of sodium alginate to chitosan is 1:1-2. Immobilizing the neutral proteases and flavor proteases with sodium alginate and chitosan improves enzyme stability and reusability, and allows the enzymes to precisely decompose precursors that produce fishy odors. Yeast further removes or masks fishy odor substances through fermentation or adsorption.

[0026] In some embodiments of the present invention, in step S2, the components of the compound antifreeze solution include, by mass, 2-4 parts trehalose, 0.5-2 parts sodium citrate, 0.2-1 parts hydroxyproline, and 100 parts deionized water, and the pH is adjusted to 6-6.8. Sodium citrate has the ability to chelate metal ions, preventing them from catalyzing lipid oxidation, and has a synergistic antifreeze effect with trehalose and other components. Hydroxyproline, as an amino acid, may provide protection by regulating osmotic pressure or by directly interacting with proteins.

[0027] In some embodiments of the present invention, in step S2, vacuum impregnation is performed at 0-4°C and a vacuum of -0.08 to -0.1 MPa for 20-40 minutes. Vacuum treatment at low temperatures effectively removes air from the fish meat tissue, and the pressure difference forces the antifreeze solution into the fish meat, achieving efficient and rapid impregnation.

[0028] In some embodiments of the present invention, in step S3, the treatment in the ultra-high pressure equipment involves holding the pressure at 200-300 MPa for 5-15 minutes. This alters the secondary and tertiary structures of myofibril proteins, causing the protein molecules to expand appropriately.

[0029] In some embodiments of the present invention, in S4, the microwave crosslinking treatment is performed at 40-50°C and a microwave power density of 0.5-1.5 W / g for 30-90 min. The mild temperature and power density activate the TG enzyme and promote crosslinking while avoiding excessive denaturation of the protein due to overheating.

[0030] In some embodiments of the present invention, the material-to-liquid ratio of the gelled fish meat and the β-cyclodextrin composite encapsulation dispersion in S4 is 1:2. Encapsulation is performed at low temperature to prevent quality changes in the fish meat before freezing.

[0031] In some embodiments of the present invention, in S5, the static magnetic field strength in the magnetoelectric coupling refrigeration device is 4-6 mT, the input voltage of the low-voltage electrostatic field is 220 V, the maximum current is 0.2 mA, and the electric field strength between the plates is 100-200 V / m.

[0032] In some embodiments of the present invention, in step S5, the β-cyclodextrin complex encapsulation dispersion comprises, by mass, 8-12 parts β-cyclodextrin, 2-3 parts maltodextrin, 0.5-1 parts fish skin collagen peptide, and 100 parts deionized water. β-cyclodextrin has a hollow structure with an internal hydrophobic and external hydrophilic component, which can encapsulate hydrophobic substances such as lipids in fish meat, inhibiting their oxidation. When combined with maltodextrin and fish skin collagen peptide, it can form a protective film on the surface of the fish meat, reducing moisture loss and protein damage during freezing.

[0033] Example 1 S1. After processing the fish, take the white meat from the back, wash it, chop it, and soak it in a sodium alginate-chitosan co-immobilized biological enzyme-yeast composite deodorizing solution with a material-liquid ratio of 1:3. Soak at 38℃ for 50 minutes, rinse and drain to obtain deodorized fish meat.

[0034] The co-immobilized bio-enzymes in the sodium alginate-chitosan co-immobilized bio-enzyme-yeast composite deodorizing solution are neutral proteases and flavor proteases. The amount of co-immobilized bio-enzymes added is 0.8% of the mass of the composite deodorizing solution, and the mass ratio of sodium alginate to chitosan is 1:1.

[0035] The preparation method of sodium alginate-chitosan co-immobilized bioenzyme-yeast composite deodorizing solution is as follows: Sodium alginate solution and a mixed suspension of neutral protease, flavor protease and yeast are mixed evenly. The resulting mixture is added dropwise to a 2% calcium chloride solution to obtain microspheres. After filtering out the microspheres, they are placed in a chitosan acetic acid solution for 30 min, crosslinked in a 0.5% glutaraldehyde solution for 2 h, repeatedly washed with deionized water, and dispersed in deionized water to obtain the composite deodorizing solution.

[0036] S2. Place the deodorized fish meat from S1 into a compound antifreeze solution, vacuum immerse it at 4℃ and -0.08MPa for 30 minutes, and then drain it to obtain pretreated deodorized fish meat.

[0037] The compound antifreeze solution contains the following components by mass: 2 parts trehalose, 0.5 parts sodium citrate, 0.2 parts hydroxyproline, and 100 parts deionized water, with the pH adjusted to 6-6.8.

[0038] The compound antifreeze solution is prepared by adding trehalose, sodium citrate and hydroxyproline sequentially to deionized water while stirring, and adjusting the pH to 6-6.8 using citric acid or sodium hydroxide to obtain the compound antifreeze solution.

[0039] S3. After vacuum packaging the pretreated deodorized fish meat obtained in S2, process it in the processing chamber of an ultra-high pressure equipment and hold it at 300MPa for 10 minutes to obtain ultra-high pressure treated fish meat.

[0040] S4. Add transglutaminase to the fish meat treated with ultra-high pressure in S3. The mass of transglutaminase is 0.2% of the fish meat treated with ultra-high pressure. After mixing evenly at 4°C, perform microwave cross-linking treatment at 45°C for 50 min at a microwave power density of 1.0 W / g to obtain the gelled fish meat.

[0041] S5. The gelled fish meat from S4 is immersed in a β-cyclodextrin composite encapsulation dispersion at a material-to-liquid ratio of 1:2. After encapsulation at 4°C for 30 minutes, it is vacuum packaged. The fish is then frozen in a magnetoelectric coupling freezing device under a static magnetic field strength of 5 mT, a low-voltage electrostatic field input voltage of 220 V, a maximum current of 0.2 mA, and an inter-plate electric field strength of 150 V / m to obtain the frozen fish product.

[0042] The β-cyclodextrin complex encapsulation dispersion comprises, by mass, 8 parts β-cyclodextrin, 2 parts maltodextrin, 0.5 parts fish skin collagen peptide, and 100 parts deionized water.

[0043] The preparation method of β-cyclodextrin complex encapsulation dispersion is as follows: heat all deionized water to 55℃, add β-cyclodextrin and stir until dissolved, then add maltodextrin and continue stirring until completely dissolved, slowly add fish skin collagen peptide while maintaining the temperature, stir at 300 rpm for 1.5 h, stop heating and cool naturally to room temperature to obtain a milky white dispersion, namely β-cyclodextrin complex encapsulation dispersion.

[0044] Example 2 S1. After processing the fish, take the white meat from the back, wash it, chop it, and soak it in a sodium alginate-chitosan co-immobilized biological enzyme-yeast composite deodorizing solution with a material-liquid ratio of 1:3. Soak at 38℃ for 50 minutes, rinse and drain to obtain deodorized fish meat.

[0045] The co-immobilized bio-enzymes in the sodium alginate-chitosan co-immobilized bio-enzyme-yeast composite deodorizing solution are neutral proteases and flavor proteases. The amount of co-immobilized bio-enzymes added is 1.2% of the mass of the composite deodorizing solution, and the mass ratio of sodium alginate to chitosan is 1:2.

[0046] The preparation method of sodium alginate-chitosan co-immobilized bioenzyme-yeast composite deodorizing solution is as follows: Sodium alginate solution and a mixed suspension of neutral protease, flavor protease and yeast are mixed evenly. The resulting mixture is added dropwise to a 2% calcium chloride solution to obtain microspheres. After filtering out the microspheres, they are placed in a chitosan acetic acid solution for 30 min, crosslinked in a 0.5% glutaraldehyde solution for 2 h, repeatedly washed with deionized water, and dispersed in deionized water to obtain the composite deodorizing solution.

[0047] S2. Place the deodorized fish meat from S1 into a compound antifreeze solution, vacuum immerse it at 4℃ and -0.08MPa for 30 minutes, and then drain it to obtain pretreated deodorized fish meat.

[0048] The compound antifreeze solution contains, by mass, 4 parts trehalose, 2 parts sodium citrate, 1 part hydroxyproline, and 100 parts deionized water, with the pH adjusted to 6-6.8.

[0049] The compound antifreeze solution is prepared by adding trehalose, sodium citrate and hydroxyproline sequentially to deionized water while stirring, and adjusting the pH to 6-6.8 using citric acid or sodium hydroxide to obtain the compound antifreeze solution.

[0050] S3. After vacuum packaging the pretreated deodorized fish meat obtained in S2, process it in the processing chamber of an ultra-high pressure equipment and hold it at 300MPa for 10 minutes to obtain ultra-high pressure treated fish meat.

[0051] S4. Add transglutaminase to the fish meat treated with ultra-high pressure in S3. The mass of transglutaminase is 0.6% of the fish meat treated with ultra-high pressure. After mixing evenly at 4°C, microwave cross-linking treatment is carried out at 45°C for 50 min at a microwave power density of 1.0 W / g to obtain the gelled fish meat.

[0052] S5. The gelled fish meat from S4 is immersed in a β-cyclodextrin composite encapsulation dispersion at a material-to-liquid ratio of 1:2. After encapsulation at 4°C for 30 minutes, it is vacuum packaged. The fish is then frozen in a magnetoelectric coupling freezing device under a static magnetic field strength of 5 mT, a low-voltage electrostatic field input voltage of 220 V, a maximum current of 0.2 mA, and an inter-plate electric field strength of 150 V / m to obtain the frozen fish product.

[0053] The β-cyclodextrin complex encapsulation dispersion comprises, by mass, 12 parts β-cyclodextrin, 3 parts maltodextrin, 1 part fish skin collagen peptide, and 100 parts deionized water.

[0054] The preparation method of β-cyclodextrin complex encapsulation dispersion is as follows: heat all deionized water to 55℃, add β-cyclodextrin and stir until dissolved, then add maltodextrin and continue stirring until completely dissolved, slowly add fish skin collagen peptide while maintaining the temperature, stir at 300 rpm for 1.5 h, stop heating and cool naturally to room temperature to obtain a milky white dispersion, namely β-cyclodextrin complex encapsulation dispersion.

[0055] Example 3 S1. After processing the fish, take the white meat from the back, wash it, chop it, and soak it in a sodium alginate-chitosan co-immobilized biological enzyme-yeast composite deodorizing solution with a material-liquid ratio of 1:3. Soak at 38℃ for 50 minutes, rinse and drain to obtain deodorized fish meat.

[0056] The co-immobilized bio-enzymes in the sodium alginate-chitosan co-immobilized bio-enzyme-yeast composite deodorizing solution are neutral proteases and flavor proteases. The amount of co-immobilized bio-enzymes added is 1% of the mass of the composite deodorizing solution, and the mass ratio of sodium alginate to chitosan is 1:1.5.

[0057] The preparation method of sodium alginate-chitosan co-immobilized bioenzyme-yeast composite deodorizing solution is as follows: Sodium alginate solution and a mixed suspension of neutral protease, flavor protease and yeast are mixed evenly. The resulting mixture is added dropwise to a 2% calcium chloride solution to obtain microspheres. After filtering out the microspheres, they are placed in a chitosan acetic acid solution for 30 min, crosslinked in a 0.5% glutaraldehyde solution for 2 h, repeatedly washed with deionized water, and dispersed in deionized water to obtain the composite deodorizing solution.

[0058] S2. Place the deodorized fish meat from S1 into a compound antifreeze solution, vacuum immerse it at 4℃ and -0.08MPa for 30 minutes, and then drain it to obtain pretreated deodorized fish meat.

[0059] The compound antifreeze solution contains the following components by mass: 3 parts trehalose, 1 part sodium citrate, 0.8 parts hydroxyproline, and 100 parts deionized water, with the pH adjusted to 6-6.8.

[0060] The compound antifreeze solution is prepared by adding trehalose, sodium citrate and hydroxyproline sequentially to deionized water while stirring, and adjusting the pH to 6-6.8 using citric acid or sodium hydroxide to obtain the compound antifreeze solution.

[0061] S3. After vacuum packaging the pretreated deodorized fish meat obtained in S2, process it in the processing chamber of an ultra-high pressure equipment and hold it at 300MPa for 10 minutes to obtain ultra-high pressure treated fish meat.

[0062] S4. Add transglutaminase to the fish meat treated with ultra-high pressure in S3. The mass of transglutaminase is 0.5% of the fish meat treated with ultra-high pressure. After mixing evenly at 4°C, microwave cross-linking treatment is carried out at 45°C for 50 min at a microwave power density of 1.0 W / g to obtain the gelled fish meat.

[0063] S5. The gelled fish meat from S4 is immersed in a β-cyclodextrin composite encapsulation dispersion at a material-to-liquid ratio of 1:2. After encapsulation at 4°C for 30 minutes, it is vacuum packaged. The fish is then frozen in a magnetoelectric coupling freezing device under a static magnetic field strength of 5 mT, a low-voltage electrostatic field input voltage of 220 V, a maximum current of 0.2 mA, and an inter-plate electric field strength of 150 V / m to obtain the frozen fish product.

[0064] The β-cyclodextrin complex encapsulation dispersion comprises, by mass, 10 parts β-cyclodextrin, 2.5 parts maltodextrin, 0.8 parts fish skin collagen peptide, and 100 parts deionized water.

[0065] The preparation method of β-cyclodextrin complex encapsulation dispersion is as follows: heat all deionized water to 55℃, add β-cyclodextrin and stir until dissolved, then add maltodextrin and continue stirring until completely dissolved, slowly add fish skin collagen peptide while maintaining the temperature, stir at 300 rpm for 1.5 h, stop heating and cool naturally to room temperature to obtain a milky white dispersion, namely β-cyclodextrin complex encapsulation dispersion.

[0066] Comparative Example 1 Compared with Example 3, this comparative example did not include the sodium alginate-chitosan co-immobilized bioenzyme-yeast composite deodorizing solution, the compound antifreeze solution, and the β-cyclodextrin composite encapsulation dispersion; all other steps were the same as in Example 3.

[0067] Comparative Example 2 Compared with Example 3, in this comparative example, the white meat from the back of the fish was processed, washed, chopped, vacuum-packed, and then frozen in a conventional manner.

[0068] Comparative Example 3 The difference between this comparative example and Example 3 is that steps S3-S5 were not performed, and the pre-treated deodorized fish meat was directly frozen in a conventional manner.

[0069] Performance testing The water-holding capacity, myofibrillar protein solubility, total sulfhydryl content, protein secondary structure disruption, and textural properties of the frozen fish products obtained in Examples 1-3 and Comparative Examples 1-3 were tested, and the results are as follows: Figure 1 As shown in Table 1.

[0070] Table 1 Performance data of Examples 1-3 and Comparative Examples 1-3

[0071] From Table 1 and Figure 1 It can be seen that the conventional freezing method used in Comparative Example 2 resulted in the worst performance. Compared with Comparative Examples 1-3, the sodium alginate-chitosan co-immobilized enzyme-yeast composite deodorizing solution, compound antifreeze solution, and β-cyclodextrin composite embedding dispersion used in Examples 1-3, along with ultra-high pressure treatment and magnetoelectric coupling freezing, showed particularly outstanding protective effects on protein solubility, thiol retention rate, and α-helical structure.

[0072] SEM testing was performed on the frozen fish products in Example 3, and the results are as follows: Figure 2 As shown, the three-dimensional network of proteins fixed and strengthened under multiple treatments exhibits a sheet structure. After the freeze-drying process, serrated tear edges and pores are produced, but no large ice crystal cavities appear, and the skeleton maintains a certain degree of continuity.

[0073] Therefore, this invention employs the aforementioned freezing method that utilizes a magnetoelectric coupling field to inhibit myofibrillar protein denaturation. It uses a static magnetic field coupled with a low-voltage electrostatic field for freezing. The 4-6 mT static magnetic field can regulate the hydrogen bond arrangement of water molecules within the fish meat, inhibiting the formation of large ice crystals and ensuring that the ice crystals formed during freezing are small and evenly distributed, preventing ice crystals from piercing muscle cells and damaging the protein's spatial structure. The 100-200 V / m low-voltage electrostatic field can maintain the polarity balance of protein molecules, inhibiting the unfolding, aggregation, and denaturation of myofibrillar proteins, thus maximizing the preservation of myofibrillar protein's solubility, gel activity, and functional properties.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A freezing method for inhibiting myofibrillar protein denaturation using a magnetoelectric coupling field, characterized in that: Includes the following steps: S1. After processing the fish, take the white meat from the back, wash it, chop it, soak it in the compound deodorizing solution, soak it at 30-40℃ for 30-60 minutes, rinse it and drain it to get the deodorized fish meat. S2. Place the deodorized fish meat from S1 into a compound antifreeze solution, vacuum impregnate and then drain to obtain pre-treated deodorized fish meat. S3. After vacuum packaging the pretreated deodorized fish meat obtained in S2, it is processed in the processing chamber of an ultra-high pressure equipment to obtain ultra-high pressure treated fish meat. S4. Add transglutaminase to the fish meat treated with ultra-high pressure in S3. The mass of transglutaminase is 0.2-0.6% of the fish meat treated with ultra-high pressure. After mixing evenly at 4°C, microwave cross-linking treatment is performed to obtain the gelled fish meat. S5. The fish meat that has undergone gelation treatment in S4 is immersed in a β-cyclodextrin composite encapsulation dispersion, encapsulated at 4°C for 20-40 min, and then vacuum-packed and frozen in a magnetoelectric coupling freezing device to obtain frozen fish products.

2. The freezing method for inhibiting myofibrillar protein denaturation using a magnetoelectric coupling field according to claim 1, characterized in that: In S1, the composite deodorizing solution is a sodium alginate-chitosan co-immobilized biological enzyme-yeast composite deodorizing solution, and the soaking material-liquid ratio is 1:

3.

3. The freezing method for inhibiting myofibrillar protein denaturation using a magnetoelectric coupling field according to claim 2, characterized in that: The co-immobilized bio-enzymes in the sodium alginate-chitosan co-immobilized bio-enzyme-yeast composite deodorizing solution are neutral proteases and flavor proteases. The amount of co-immobilized bio-enzymes added is 0.8-1.2% of the mass of the composite deodorizing solution, and the mass ratio of sodium alginate to chitosan is 1:1-2.

4. The freezing method for inhibiting myofibrillar protein denaturation using a magnetoelectric coupling field according to claim 1, characterized in that: In S2, the components of the compound antifreeze solution include 2-4 parts trehalose, 0.5-2 parts sodium citrate, 0.2-1 parts hydroxyproline, and 100 parts deionized water by mass, and the pH is adjusted to 6-6.

8.

5. The freezing method for inhibiting myofibrillar protein denaturation using a magnetoelectric coupling field according to claim 1, characterized in that: In S2, vacuum impregnation is performed at 0-4℃ and a vacuum of -0.08 to -0.1 MPa for 20-40 minutes.

6. The freezing method for inhibiting myofibrillar protein denaturation using a magnetoelectric coupling field according to claim 1, characterized in that: In S3, the ultra-high pressure equipment is subjected to a pressure holding period of 200-300MPa for 5-15 minutes.

7. The freezing method for inhibiting myofibrillar protein denaturation using a magnetoelectric coupling field according to claim 1, characterized in that: In S4, the microwave crosslinking treatment is performed at 40-50℃ with a microwave power density of 0.5-1.5W / g for 30-90 minutes.

8. The freezing method for inhibiting myofibrillar protein denaturation using a magnetoelectric coupling field according to claim 1, characterized in that: The material-to-liquid ratio of the gelled fish meat and β-cyclodextrin composite encapsulation dispersion in S4 is 1:

2.

9. A freezing method for inhibiting myofibrillar protein denaturation using a magnetoelectric coupling field according to claim 1, characterized in that: In S5, the static magnetic field strength in the magnetoelectric coupling refrigeration equipment is 4-6 mT, the input voltage of the low-voltage electrostatic field is 220 V, the maximum current is 0.2 mA, and the electric field strength between the plates is 100-200 V / m.

10. A freezing method for inhibiting myofibrillar protein denaturation using a magnetoelectric coupling field according to claim 1, characterized in that: In S5, the β-cyclodextrin complex encapsulation dispersion comprises, by mass, 8-12 parts of β-cyclodextrin, 2-3 parts of maltodextrin, 0.5-1 parts of fish skin collagen peptide, and 100 parts of deionized water.

Images